1. Field of the Invention
The invention relates to a closing device for a milking device and to a milking device provided with one or a plurality of such closing devices.
2. Description of the Related Art
In milking devices a milk line leads from one or more milk taking devices for taking milk from animals, such as milking robots, via a milk jar, to a central, cooled milk storage. For hygienic reasons, a frequent cleaning of the milk line is required.
In one approach, a discharge line is connected for this purpose, by means of a three-way valve, in the milk line portion shortly upstream of the milk tank. The discharge line leads to the sewer. After reversing the three-way valve in order to close the passage to the milk tank, cleaning liquid is supplied at the entrance of the milk line, which cleaning liquid subsequently flows via the three-way valve and the discharge line into the sewer.
In another approach, as shown in U.S. Pat. No. 4,222,346, there is disposed in the milk line a slide valve, the slide of which is provided with a passage having a connection to the upstream portion of the milk line that leads to a milk claw. The (relatively stationary) house of the valve, in which the slide is slidable in a reciprocating manner, is provided with two passages which connect to the downstream portion of the milk line and a conduit to a source of rinsing liquid, respectively. The slide is slidable between a milking position in which the milk line is in the flow through position, a rinsing position in which the upstream portion is in connection with the passage to the conduit to the source of rinsing liquid, and a neutral drainage position situated therebetween in which the downstream portion of the milk line and the conduit of the source of rinsing liquid are closed and the upstream portion of the milk line opens in a cavity in the slide valve. Sealing of the passage to the downstream portion of the milk line with respect to the slide takes place by means of an O-ring along which the slide is moved. Sealing of the passage for the rinsing liquid with respect to the slide takes place by means of a hollow, spring-loaded teflon plug.
Another slide valve having a milk line connection provided on the slide forms the subject of U.S. Pat. No. 4,034,713.
Hygiene in milk line systems is subjected to strict standards. Rinsing liquid should be prevented from entering the milk line portion that leads to the milk storage.